Not to be harsh, but this is a situation where reading the key fare rules at the time of booking was in order. But, not having done that, it sounds as though OP still has not done so.

OP will need to confirm this for certain, but:

1. If he simply wishes to cancel his ticket, he will have a $1,450 credit to use for another ticket and will pay $200 at the time he rebooks.
2. If this is an odd refundable fare with a penalty, he will indeed be due a refund of $1,250.
3. If OP has new dates in mind, he will have a credit of $1,450, pay $200 and then any fare difference which may be due for the new tickets. If that fare difference is now $300, he will need to pay $500 for the new dates he has selected.

Depending on the nature of the family medical emergency, this may all be covered by travel insurance.

If not covered by insurance, this is where one tries a short and sweet request to have the change fee waived. It is unlikely that any new fare differential will be waived, but that would bring the change down to $300.